The existing lender seems to be buying these shares, so perhaps it is they who are deciding how much they want to buy. Perhaps Sirius XM is trying to lessen the effect of share dilution by floating shares in relatively small amounts.

I find it is interesting that the last couple of these relatively small stock issuances have each been at a price above the current trading price. Perhaps there is some legal reason for this.

I also find it interesting that the current lender would be interested in obtaining stock instead of cash that is owed to them. Perhaps these are agreed upon actions as part of a deal for future financing?